My kids both had merit scholarships that were good for 8 CONSECUTIVE semesters, had a required gpa and a few other things to check off (good standing, for example). The Florida Bright Futures required 12 credits per semester and certain courses did not count (remedial courses, repeated courses) and once you lost the award it could not be reinstated.
What happened to both kids was the schools changed the award programs after they started and they both were ‘stuck’ with the program as they received it. One had a set amount that was a lot lower than the next admitted class, so while freshmen were getting $2-3k more, they were all paying the same tuition. The other had a set scholarship and 2 smaller grants. The school eliminated the 2 grants and increased the merit amount for the incoming class, so those on the ‘old’ program got less. Still kept the grants, but they weren’t as much as the increased grants the new kids got.
I think schools do keep their promises, and if you meet the renewal requirements you’ll keep your award.